Comments on: Sizing for Dummies

By: Saravana Babu

Saravana Babu — Thu, 16 Jun 2011 19:36:27 +0000

please send me worked examples of sizing for my reference. saravanababumr@yahoo.com

By: Son Deida

Son Deida — Thu, 08 Jul 2010 10:10:14 +0000

I am a frequent reader of your blog posts. I liked the recent one and other posts on your blog so much that I have subscribed to the blog’s RSS feed in Thunderbird. Even thinking of stealing some ideas and put them to work. Keep all the good work going by posting more informative posts. Thank you. Time well spent on this post.

By: apoorv

apoorv — Wed, 30 Nov -0001 00:00:00 +0000

I am not. That is your assumption. All I am suggesting is that you use an “appropriate” benchmark application. If you donot get a reasonably “close” benchmark, you take the next best available and make assumptions.BTW, these vendors will give you benchmarks on all kinds of hardware. I have results for the same application on Intel and Solaris from one vendor.

By: Anonymous

Anonymous — Wed, 30 Nov -0001 00:00:00 +0000

Too many assumptions. Not to mention the question mark on the initial benchmark application itself. Even for budgetary estimates it sounds a little too stretched.I would go for using empirical data of perf reqts and use standard formulae for TPS, THS and required response time. As pointed by you in your first option,I feel that is more optimal than the last one. Finally its left to one’s own experience and judgement on which method to follow.

By: apoorv

apoorv — Wed, 30 Nov -0001 00:00:00 +0000

Correct. If you have all that data that is required for using so called standard formulae, please use them. Infact that should be the preferred approach.I will repeat however that what i’ve written about is for a scenario when you donot have any of this information or the client does not want to share this information. You can obviously say NO to the client or make assumptions and give him something. If you work in an Indian company (like I do), I am sure you will understand what i mean. Frequently, we have to give “reccos” to clients without knowing anything and that is when this approach has proven useful for me.

By: apoorv

apoorv — Wed, 30 Nov -0001 00:00:00 +0000

It depends on which benchmarks you use. As an example, i know BEA provides application stats with varying loads.Also remember, this is not exact sizing. This is only a baseline to be considered during pre-sales stage.

By: Anonymous

Anonymous — Wed, 30 Nov -0001 00:00:00 +0000

Does the benchmark application also provide what kind of performance stats it supports? How does one extrapolate these data points to what one’s own app requires. It is a well known fact that the perf stats for say 50,000 hits a day cannot be linearly extrapolated to 5 million hits a day. Any extrapolation, based on any assumptions is at best only a vague guess and may prove to be a costly mistake.

By: apoorv

apoorv — Wed, 30 Nov -0001 00:00:00 +0000

BEA does. Oracle does and so does IBM.Also, in this stage the assumption is that you donot even know how many portlets, haw many database queries etc are there. In such a scenario, I donot think that baseline numbers for BEA would be drastically different from those of IBM.Have you ever seen an application that uses 2 machines with BEA and 10 with IBM?? Usually the difference is not much

By: Anonymous

Anonymous — Wed, 30 Nov -0001 00:00:00 +0000

All portal server products will use their entire app server stack too. So essentially you are extrapolating the performance of the portal to the entire stack of the products (app server, integration stack, middle layer and in case of Oracle – database too). That I believe is not the correct way to do it.The performance stats for a complete product stack does considerably vary.Also, what about the hardware stack? The sample application may be benchmarked using HP. What if your stack is Sun or IBM (or even Dell for that matter)?Add another assumption to your already long list.Where are we headed ?

By: Anonymous

Anonymous — Wed, 30 Nov -0001 00:00:00 +0000

The third approach looks inaccurate. More than anything else – its a sample application against which you are benchmarking. This application may not have been tested with real life loads of millions of hits, thousands of hits per second etc etc. So the how this sample app scales up is not clearly known. To size your app against this certainly seems immature.